The invention relates to a thermal printer having a ribbon feeder.
Thermal printers with a cutter generally forward-feed a sheet to the cutter position after printing and then back-feed the cut end of the sheet to the print start position. In this case, the sheet, being in contact with a ribbon is back-fed, so that the ribbon is made to be back-fed together with the sheet. When the ribbon is back-fed, the ribbon becomes slack. This may cause abnormal feeding of the ribbon for the next printing or wrinkling the ribbon, which may lead to undesired problems such as defective printing.
In order to overcome such problems, the following techniques have been conventionally employed. In a first technique, a platen roller is separated from a thermal head to thereby stop the ribbon and back-feed only the sheet. In a second technique, a ribbon feed roller is reversely rotated simultaneously with the back-feeding of the sheet to thereby return the ribbon in an direction opposite to the ribbon feed direction. However, such techniques also have problems, such as making the control system of the thermal printer complicated and increasing the size of the thermal printer.